* {
    margin: 0;
    padding: 0;
}

body {
    height: 100vh;
    /* vh表示 view height 视图窗口的高度 */
    background: #4c4c4c url('https://unsplash.it/1500/900?image=1021');
    background-size: cover;
    display: flex;
    justify-content: center;
    align-items: center;
}

.wrapper {
    display: flex;
    width: 850px;
}

.flex {
    width: 765px;
    height: 430px;
}

.speed {
    flex: 1;
    /* 继承父容器所有的可用宽度 */
    display: inline-block;
    background: #fff;
    margin: 10px;
    border-radius: 50px;
    overflow: hidden;
    /* 超出即隐藏 */
}

.speed-bar {
    width: 100%;
    height: 16.3%;
    background: linear-gradient(to bottom, #1279c7, #6fc712);

    display: flex;
    justify-content: center;
    align-items: center;

    color: #fff;
}